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Omethoate (Ref: ENT 25776)
Last updated: 18/08/2021
(Also known as: dimethoate-met; dimethoxon)

SUMMARY
Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate Ecotoxicity Human health
Environmental fate
High alert:
Drainflow: Mobile
Ecotoxicity
High alert:
Birds acute ecotoxicity: High; Daphnia acute ecotoxicity: High; Daphnia chronic ecotoxicity: High; Bees acute oral ecotoxicity: High
Human health
High alert:
Mammals acute toxicity: High; Endocrine distrupter; Acetyl cholinesterase inhibitor; Neurotoxicant
GENERAL INFORMATION
Description
An insecticide and acaricide to control a wide range of pests on fruit, hops and other crops. Also a pesticide transformation product
Example pests controlled
Aphids; Mites; Caterpillars; Beetles; Mealybugs; Scale
Example applications
Fruit including citrus, apples, plum; Hops; Sugarbeet; Potatoes; Cereals; Ornamentals
Efficacy & activity
-
Availability status
Current
Introduction & key dates
circa 1960
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Expired
UK LERAP status
No UK approval for use
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
Not applicable
Date EC 1107/2009 inclusion expires
Expired
EU Candidate for substitution (CfS)
-
Listed in EU database
Yes
Approved for use (✓) under EC 1107/2009 in the following EU Member States
ATAustria
BEBelgium
BGBulgaria
CYCyprus
CZCzech Republic
DEGermany
DKDenmark
EEEstonia
ELGreece
                 
ESSpain
FIFinland
FRFrance
HRCroatia
HUHungary
IEIreland
ITItaly
LTLithuania
LULuxembourg
                 
LVLatvia
MTMalta
NLNetherlands
PLPoland
PTPortugal
RORomania
SESweden
SISlovenia
SKSlovakia
                 
Additional information
Also used in
Australia
Chemical structure
Isomerism
None
Chemical formula
C₅H₁₂NO₄PS
Canonical SMILES
CNC(=O)CSP(=O)(OC)OC
Isomeric SMILES
No data
International Chemical Identifier key (InChIKey)
PZXOQEXFMJCDPG-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C5H12NO4PS/c1-6-5(7)4-12-11(8,9-2)10-3/h4H2,1-3H3,(H,6,7)
2D structure diagram/image available?
Yes
General status
Pesticide type
Insecticide, Acaricide, Metabolite
Metabolite Type
Soil; Groundwater; Surface water; Sediment; Air
Substance group
Organophosphate
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Systemic with contact and stomach action. Cholinesterase inhibitor.
CAS RN
1113-02-6
EC number
214-197-8
CIPAC number
202
US EPA chemical code
-
PubChem CID
14210
Molecular mass
213.2
PIN (Preferred Identification Name)
-
IUPAC name
2-dimethoxyphosphinoylthio-N-methylacetamide
CAS name
O,O-dimethyl S-(2-(methylamino)-2-oxoethyl) phosphorothioate
Other status information
Chemical subject to PIC regulations; Subject to the provisions of the UK Poisons Act 1972
Relevant Environmental Water Quality Standards
UK Statutory standard for the protection of aquatic life in surface waters: 0.01 µg l⁻¹
Herbicide Resistance Classification (HRAC)
Not applicable
Herbicide Resistance Classification (WSSA)
Not applicable
Insecticide Resistance Classification (IRAC)
1B
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
Leptinotarsa decemlineata, Aonidella aurantii, Aphis gossypii, Macrosiphum avenae, Myzus persicae, many others
Physical state
Colourless liquid
Can be a metabolite of:
Parent
Formation medium
Estimated maximum occurrence fraction
1107/2009 relevancy
dimethoate Soil 0.150 Major fraction, Not relevant
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Bayer CropScience
  • King Tech Corp.
Example products using this active
  • Le-ma 290 SL
  • Atease
  • Modern
  • Folimat
Formulation and application details
Usually supplied as a soluble concentrate or emulsifiable concentrate
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
500000
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
Miscible
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone
-
Miscible
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Methanol
-
Melting point (°C)
-28
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Solidifies
-
Boiling point (°C)
135
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
-
Degradation point (°C)
- - -
Flashpoint (°C)
128
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
Octanol-water partition coefficient at pH 7, 20 °C
P
1.26 X 10-01 Calculated -
Log P
-0.9
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Low
Bulk density (g ml⁻¹)
1.32
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
19.0
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Highly volatile
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
4.62 X 10-09
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Non-volatile
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
Neutral soln: 194.4nm=6366.1
Acid soln: 207.5nm=2401.2
Basic soln: 233.5nm=3020.7
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
Surface tension (mN m⁻¹)
- - -
Degradation
Property
Value
Source; quality score; and other information
Interpretation
General biodegradability
-
Soil degradation (days) (aerobic)
DT₅₀ (typical)
0.1
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Non-persistent
DT₅₀ (lab at 20 °C)
0.1
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Non-persistent
DT₅₀ (field)
14
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
Non-persistent
DT₉₀ (lab at 20 °C)
0.6
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Non-persistent
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
EU 2017 dossier Lab studies Dt50 range 0.1-0.3 days, DT₉₀ range 0.1-1.2 days, Soils=3
Dissipation rate RL₅₀ on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ on and in plant matrix
Value
1.7
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 1.3-2.1 days, wheat, various matrices, n=3
Aqueous photolysis DT₅₀ (days) at pH 7
Value
Stable
B4 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
4 = Verified data
Stable
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
17
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
Non-persistent
Note
-
Water-sediment DT₅₀ (days)
4.5
K4 K = Research datasets, e.g. Pandora, Demetra
4 = Verified data
Fast
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
0.53
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Mobile
Koc
41.3
Notes and range
EU dossier Kd range 0.20-0.99 mL g⁻¹, Koc range16-87 mL g⁻¹, Soils=3
Freundlich
Kf
- - -
Kfoc
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
2.73 Calculated Transition state
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
1.17 X 10-01 Calculated -
Note
-
Potential for particle bound transport index
Low Calculated -
Potential for loss via drain flow
Mobile Calculated -
Other known metabolites
Metabolite name and reference
Aliases
Formation medium / Rate
Estimated maximum occurrence fraction
Metabolising enzymes
dimethylthiophosphate DMTP Mammals - -
dimethylphosphate DMP Mammals - -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
75
Q2 Q = Miscellaneous internet resources
2 = Unverified data of unknown source
Estimated
Low potential
CT₅₀ (days)
Not available -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
50.0
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
High
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
Rat
-
(ppm diet)
0.5 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
9.9
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Colinus virginianus
High
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
9.1
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
Oncorhynchus mykiss
Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.022
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
Daphnia magna
High
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.000004
P3 P = Other governments and regulators
3 = Unverified data of known source
Unknown species
High
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)
- - -
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Non-target plants
- - -
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
167.5
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
Scenedemus subspicatus
Low
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
Honeybees (Apis spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
0.048
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
High
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Bumblebees (Bombus spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
-
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
-
Mason bees (Osmia spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Other pollinators (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other pollinators (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
46
B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here )
5 = Verified data used for regulatory purposes
Eisenia andrei
Moderate
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Other soil macro-organisms
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Other arthropod (1)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Other arthropod (2)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Soil micro-organisms
- - -
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
HUMAN HEALTH AND PROTECTION
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
High (class III) - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
50.0
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
High
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
145.0
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
0.3
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat
-
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.0003
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
EU 2006
-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
0.002
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
EU 2006
-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
0.0003
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
EU 2006
-
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
List I; List II - -
Exposure Routes
Public
-
Occupational
Occupational exposure may occur through inhalation and dermal contact
MRLs
European
EU MRL pesticide database 
Great Britain
GB MRL Register 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not to cause a problem
A3 A = Chromosome aberration (EFSA database)
3 = Negative
;
D2 D = Genome mutation (EFSA database)
2 = Mixed/ambiguous results
;
C2 C = Gene mutation (EFSA database)
2 = Mixed/ambiguous results
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
Yes, known to cause a problem
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
XNo, known not to cause a problem
Yes, known to cause a problem
Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
No data found
Yes, known to cause a problem
Yes, known to cause a problem
Eye irritant Phototoxicant  
XNo, known not to cause a problem
No data found  
General human health issues
Toxic if swallowed
May cause cyanosis
Handling issues
Property
Value and interpretation
General
Flammable
CLP classification 2013
Health: H301, H312
Environment: H400
EC Risk Classification
T - Toxic: R25
Xn - Harmful: R21
N - Dangerous for the environment: R50
EC Safety Classification
S1/2, S23, S36/37, S45, S61
WHO Classification
Ib (Highly hazardous / Highly hazardous)
UN Number
3018
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
omethoate
French
omethoate
German
Omethoat
Danish
omethoate
Italian
ometoato
Spanish
ometoato
Greek
-
Polish
ometoat
Swedish
-
Hungarian
-
Dutch
-

Record last updated: 18/08/2021
Contact: aeru@herts.ac.uk
Please cite as: Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242